The present invention relates to a device and process for detecting prostatitis.
The prostate gland (or prostate) is a walnut-sized, mucous-producing organ in males that lies just below the urinary bladder. The prostate typically grows and enlarges throughout life. The only known function of the prostate is to produce a secretion that nourishes and protects the sperm during reproduction. The urethra, the canal that in most mammals discharges urine from the bladder, passes through the prostate gland. Unfortunately, this anatomical feature creates problems, often associated with difficulty in urination, as males age.
A national survey of U.S. physician visits estimated that the diagnosis of prostatitis results in 2 million office visits per year in the United States and is the most frequent diagnosis resulting in an office visit to urologists in men less than 50-years-old. Collins, M. M., et al. (1998) J. Urol. 159:1224-1228. Prostatitis is defined as an inflammation or infection of the prostate gland. While prostatitis may be acute, associated with systemic findings of fever, chills and rigors, most cases of prostatitis are chronic and tend to be incurable with relatively frequent recurrences despite optimal standard therapy. Chronic prostatitis (inflammation or infection of the prostate) is common to all adult men. It is associated with virtually all cases of prostate cancer and is present in every prostate biopsy regardless of other findings. Chronic prostatitis may not cause significant symptoms in many men, but in others it can be a devastating disease that severely affects the quality of life of those afflicted. It is difficult to diagnose and even more difficult to treat.
The most common symptom of chronic prostatitis is pelvic pain, followed by various voiding symptoms, impotence, and infertility. Pain from prostatitis is usually located in the groin, testicles, and penis, just above the rectum or in the suprapubic area over the bladder. Pain is frequently associated with ejaculation. Typical voiding symptoms produced by prostatitis include getting up at night to void (nocturia), frequency and urgency of urination, incomplete voiding, decreased force of the urinary stream, intermittency of the stream, and a need to push or strain to void. Impotence or erection difficulties and male infertility are also associated with prostatitis.
Conventional methods of detecting prostatitis include a digital rectal examination, midstream specimen of urine, specific culture, urine dipstick, and ejaculate culture. Other methods include the AUA Symptom Score, which is a survey that was drafted by the American Urologists Association and was validated in 1996. It evaluates a man""s voiding abilities. Symptom Score survey includes questions on nocturia, frequency, intermittency, incomplete elimination, stream size, urgency, and the need to strain. Respondents answer seven questions about the severity of symptoms. Respondents indicate the frequency of the events, with each frequency having an assigned score, and a diagnosis is made.
Still another method is the prostate specific antigen (PSA) test, which is a blood test that can be used to detect prostatitis. PSA is a protein substance produced by certain cells in the prostate gland. A very small amount of PSA escapes into the blood stream. Thus, PSA can be tested in the blood. Because the amount of PSA in the blood is very low, detection of it requires a very sensitive monoclonal antibody technique.
Still yet another test is one that examines expressed prostatic secretion (EPS), which is a secretion, not a body fluid. Traditionally, EPS was tested through a microscopic examination of the EPS. The prostatic secretion is obtained by gentle massage of the prostate during the digital rectal examination. When the secretion is examined under the microscope, a finding of more than 10 white blood cells per high powered field (WBCS/HPF) is considered definitive proof of inflammation and prostatitis.
While all of these tests are available, Nickel, et al. report that only 18% of primary care physicians (PCPs) and 41% of urologists said that they employed any type of specific prostate tests. Nickel, et al. (1998) Urology 52(5) 797-802. Nickel, et al. conclude from a survey of PCPs and urologists that there is widespread frustration, discomfort, and a lack of confidence in their perceived ability to manage prostatitis. Specifically, physicians have expressed a high degree of frustration and unhappiness in dealing with prostatitis, which was driven by a lack of confidence and comfort in their ability to accurately diagnose and subsequently rationalize treatment of prostatitis. The surveyed physicians expressed a desire for a simpler and clearer diagnostic guidelines.
Simpler and clearer diagnostic guidelines are provided by the invention described herein. The invention includes a method for detecting prostatitis using a device, such as a dipstick, to test for white blood cells in EPS. Dipsticks are currently used to test for multiple analytes, such as glucose and protein. For example, a dipstick that detects neutrophil defensins to diagnose reproductive tract inflammation and preeclampsia is described in U.S. Pat. No. 5,972,594 to Heine.
Dipsticks and related components that detect leukocytes and leukocyte enzymes in body fluids have been patented. For example, U.S. Pat. No.4,758,508 to Schnabel, et al. describes an agent and a method for detecting esterolytic and/or proteolytic enzymes in body fluids. U.S. Pat. No. 4,637,979 to Skjold, et al. describes a composition and test device for determining the presence of leukocytes in test samples including body fluids such as urine. U.S. Pat. No. 4,645,842 describes pyrrole compounds, and U.S. Pat. No. 4,704,460 (both to Corey) describes novel compounds for detecting the presence of hydrolytic analytes including leukocytes, esterase, and protease, in a test sample, including urine. U.S. Pat. No. 4,774,340 to Corey describes a method for preparing 3-hydroxy pyrroles and esters thereof, which are used to test samples including urine. A composition and test device for determining the presence of leukocytes, esterase, and protease in a body fluid including urine is described in U.S. Pat. No. 4,657,855 to Corey, et al. A method for determining the concentration of white blood cells in urine or other biological fluid is described in U.S. Pat. No. 5,663,044 to Noffsinger, et al. A method for preparing an ester used to detect leukocyte cells, esterase, and protease in body fluids such as urine is described in U.S. Pat. No. 4,716,236 to Ward, et al. All of these patents, which are incorporated herein by reference, correlate an abnormally high level of leukocytes in a patient""s urine with the possible indication of pathological conditions such as kidney or urogenital tract infection or other dysfunction.
However, none of the above-noted approaches provides a rapid and economical method of detecting prostatitis. More particularly, none of these use EPS as a test sample. Such a method, described herein, provides a rapid and economical method for detecting prostatitis.
A principal aim of the invention is to provide a method for detecting prostatitis that includes using a device, such as a dipstick, to test expressed prostatic secretion (EPS).
A further aim of the present invention is to provide a device, such as a dipstick, for detecting prostatitis that includes an indication of the presence or absence of prostatitis.
In short, the invention described herein is directed to a method of detecting prostatitis comprising obtaining an expressed prostatic secretion from a patient; contacting a device having diagnostic test reagents to the expressed prostatic secretion, the diagnostic test reagents reacting with the expressed prostatic secretion to produce a change in the device; reading the change in the device to produce a positive or negative experimental test result, wherein the experimental test result is positive when the experimental test result is pre-determined to correspond with a number above 10 for the number of white blood cell per high powered field and the experimental test result is negative when the experimental test result corresponds with a number of 10 or less for the number of white blood cell per high powered field; and determining presence of prostatitis with the positive experimental test result and the absence of prostatitis with the negative experimental test result.
The invention also provides a device for detecting prostatitis from an expressed prostatic secretion using a dipstick comprising a matrix having diagnostic test reagents that react with the expressed prostatic secretion by detecting leukocytes or a leukocyte enzyme, the matrix having two portions, wherein a first portion indicates the presence of prostatitis and a second portion indicates the absence of prostatitis; a mounting substrate, the matrix attached to the mounting substrate, wherein the device produces a visual change in the matrix upon contact of the matrix with the expressed prostatic secretion, the first indicator producing a positive experimental test result, and the second indicator producing a negative experimental result; wherein the experimental test result is positive when the experimental test result is pre-determined to correspond with a number above 10 for the number of white blood cell per high powered field and the experimental test result is negative when the experimental test result corresponds with a number of 10 or less for the number of white blood cell per high powered field; and wherein the test device determines the presence of prostatitis with the positive experimental test result and the absence of prostatitis with the test negative experimental result.
Described herein is a method to detect rapidly and economically prostatitis using a device (preferably a dipstick) to test expressed prostatic secretion (EPS). EPS is a secretion, not a body fluid. Traditionally, EPS was examined microscopically. If more than 10 WBCS/HPF were detected with the microscope, a diagnosis of prostatitis resulted. The subject invention tests EPS with a device that has diagnostic test reagents that detect leukocytes and/or leukocyte enzymes. Study results show that the subject invention provides test results that correlate 97.5% with test results obtained through conventional microscopy. Patient examples indicate that testing EPS, as opposed to bodily fluids such as ejaculate and urine, provides more accurate detection of prostatitis. Thus, EPS is a better indicator of prostate health than bodily fluids such as ejaculate.
Of particular utility is that the subject invention provides a method for detecting prostatitis that is faster and more economical when compared to conventional methods of testing for prostatitis. The subject invention eliminates the need for a microscope and provides a more accurate diagnosis for prostatitis. Because microscopes will no longer be needed to diagnose prostatitis, the subject invention reduces the laboratory procedure for these assays from a cumbersome counting procedure requiring microscopic observation, to a rapid, facile dip-and-read operation. Furthermore, this invention permits testing of prostatitis in areas that do not have the necessary equipment, reduces the costs associated with testing for prostatitis, and provides physicians with the confidence and ability to accurately diagnose prostatitis.
Further aims, objects, and advantages of the invention will become apparent upon a complete reading of the Detailed Description and attached claims, which follow.
The invention uses expressed prostatic secretion (EPS) as the test sample. EPS is not a body fluid, such as urine or blood. Instead, EPS is a secretion. EPS does not move around and does not flow. It actually has characteristics more like mucus. EPS is present within the prostate intracellularly and intraductually. The EPS sample is obtained by gentle massage of the prostate during the digital rectal examination during which the prostate is pressed upon, and the EPS is expressed. Traditionally, the secretion was examined under the microscope. A finding of more than 10 white blood cells per high powered field (WBCS/HPF) was considered definitive proof of inflammation and prostatitis.
A first embodiment of the invention is a method for detecting prostatitis using a device, such as a dipstick, having diagnostic test reagents to detect prostatitis. The diagnostic test reagents react with the test sample to produce a change upon contact with the EPS. The test sample is EPS. Test results showed a 97.5% correlation between (1) conventional prostatitis detection using a microscope to count the number of leukocytes in an EPS sample and (2) the subject invention, which uses a device to detect leukocytes and/or leukocyte enzymes in an EPS sample. A second embodiment of the invention is a device, such as a dipstick, that has (1) a positive indication for the presence of prostatitis and (2) a negative indication for the absence of prostatitis. The difference between the positive indication and the negative indication is pre-determined.
The method: The subject method begins with obtaining a EPS sample from a symptomatic patient. Symptomatic patients are identified as described below. Once the sample is obtained, a device having diagnostic test reagents that detect leukocytes and/or a leukocyte enzyme is contacted with the EPS. Depending on the type of device used, a certain amount of time might have to pass before the device is read. For example, when using a MULTISTIX-2 by Bayer Aktiengesellschaft (Fed. Rep. Germany) two minutes pass between the time that the device is contacted with the sample and when it is read to produce an experimental test result. The MULTISTIX-2 dipstick is sold to test urine. In the subject method, it is used to test EPS. The experimental test result is then compared to pre-determined test results that indicates either the presence or absence of prostatitis.
The subject method can use a quantitative device (such as the MULTISTIX-2, MULTISTIX-10, URISTIX-4, or any leukocyte-detecting device) or the subject inventive device that has two indications, one for a positive result and one for a negative result. When using a quantitative device, it produces a range of results. For example, the MULTISTIX-2 produce quantitative results of 0, trace, +1, +2 and +3. Quantitative results also include xe2x80x9cBetween +1 and +2xe2x80x9d and xe2x80x9cBetween +2 and +3.xe2x80x9d A test result of 0, trace, and +1 corresponds to 10 or less WBCS/HPF (i.e., the absence of prostatitis). A test result of Between +1 and +2, Moderate (+2), Between +2 and +3, and Large (+3) corresponds to greater than 10 WBCS/HPF (i.e., the presence of prostatitis). The pre-determination is done using a study such as the one detailed below in the Test Example. When the experimental test result correlates to 10 or less WBCS/HPF, this leads to a indication of an absence of prostatitis. Conversely, when the experimental test result correlates to more than 10 WBCS/HPF, this leads to an indication of a presence of prostatitis.
Symptomatic patients are identified using the Lower Tract Symptom Survey reprinted below. Symptomatic patients can also be selected based on a number of different criteria. For example, the AUA Symptom Score, mentioned above, can be used. Prostatitis patients generally are symptomatic, exhibiting significant voiding symptoms. Likewise, it would not be unusual for men with prostatitis to have an elevated PSA. Any of the criteria listed in the Related Art section or any other known in the art can be used with equal efficiency to identify symptomatic patients.
The device: The subject device used in the subject invention includes (1) a matrix (preferably filter paper) with diagnostic test reagents and (2) a mounting substrate (preferably polystyrene film), which typically does not absorb the test sample, such that the user can hold onto the substrate without contacting the sample. The device produces a visual change in the matrix upon contact with EPS. The matrix has two indicators-a first that indicates the presence of prostatitis and a second that indicates the absence of prostatitis. The first indicator produces a positive experimental test result and the second indicator produces a negative experimental result. The experimental test result is positive when the experimental test result is pre-determined to correspond with a number above 10 WBCS/HPF. Conversely, the experimental test result is negative when the experimental test result is pre-determined to correspond with a number of 10 or less WBCS/HPF. The subject device determines the presence of prostatitis with the positive experimental test result and the absence of prostatitis with the negative experimental test result.
The diagnostic test reagents may be associated with the matrix by any physical or chemical means, including, for example impregnation, coating, linking, and covalent attachment. The matrix may take any convenient physical form, such as a card, pad, strip, or dipstick. The diagnostic test reagents detect leukocytes and/or a leukocyte enzyme, such as leukocyte esterase, and esterolytic and proteolytic enzymes. Such diagnostic test reagents include the compositions of the above-referenced patents, including an ester (preferably a chromogenic ester) and a diazonium salt such as those described in U.S. Pat. No. 4,637,979. Another preferred reagent is a derivatized pyrrole amino acid ester, a diazonium salt, a buffer, and non-reactive ingredients as described in U.S. Pat. Nos. 4,645,842; 4,637,979; 4,657,855; 4,704,460; 4,758,508; and 4,774,340. The preferred amounts of these ingredients is based on dry weight at the time of impregnation and is as follows: about 0.4% w/w derivatized pyrrole amino acid ester, about 0.2% w/w diazonium salt, about 40.9% w/w buffer, and about 58.5% w/w non-reactive ingredients.
The inventive device has one indication of the presence of prostatitis and a second indication for the absence of prostatitis. The two indications preferably are a negative (xe2x88x92) symbol and a positive (+) symbol, but could be any two indications. One embodiment of the device has the negative indication (e.g., the xe2x80x9cxe2x88x92xe2x80x9d portion of a possible xe2x80x9c+xe2x80x9d symbol) containing reagents that reacts with all samples. That is, the diagnostic test reagents react to some constituent analyte, such as urobilinogen, which is present in all samples. Alternatively, the diagnostic test reagents test an aspect of the sample, such as pH, that every sample has. The positive indication (e.g., the xe2x80x9c|xe2x80x9d portion of a xe2x80x9c+xe2x80x9d symbol) contains a reagent that the reacts only with samples containing a count of more than 10 WBCS/HPF. Another embodiment has the negative indicator (e.g., the xe2x80x9cxe2x88x92xe2x80x9d portion of a possible xe2x80x9c+xe2x80x9d symbol) having a higher sensitivity to leukocytes or a leukocyte enzyme such that it reacts to samples containing any number of leukocytes. The positive indication (e.g., the xe2x80x9c|xe2x80x9d part of the xe2x80x9c+xe2x80x9d symbol) has a lower sensitivity such the reagents react only with samples containing a count of more than 10 WBC/HPF.
Another version of the subject device has text on the device in two places. In one place the text indicates a positive result. In another, it indicates a negative result. Next to the indications are matrices having the appropriate diagnostic test reagents. For example, next to the negative indication is a matrix having diagnostic test reagents that react with all samples. Next to the positive indication is a matrix having diagnostic test reagents that react only with samples that have more than 10 WBCS/HPF. The subject device, such as one of the examples above, does not require a chart, such as coloration chart, to interpret the results. This aspect of the invention makes the device (and the corresponding method) an even more rapid device (and method) for detecting prostatitis.